1. Field of the Invention
The invention pertains to spring biased caster wheels capable of vertical adjustment wherein a uniform biasing force is maintained on the caster wheel regardless of its vertical adjustment.
2. Description of the Related Art
Caster wheels capable of vertical adjustment with respect to the supporting frame are known, but if the caster wheel is to be spring biased or suspended, difficulty is encountered in producing a uniform biasing force on the caster wheel regardless of its vertical position.
In hand operated fork lifts, for instance, spring biased heavy duty caster wheels are employed. It is desirable to permit such caster wheels to be vertically positionable for a number of reasons, including wheel wear and floor clearance, but it is important that the spring biasing force on the caster wheel be uniform regardless of the caster wheel vertical position. In known spring biased caster wheel constructions, difficulty has been encountered in maintaining a uniform biasing force on the caster wheel as the vertical position of the wheel is adjusted.
Because of the concise configuration of caster wheels, it is difficult to incorporate spring biasing means within the caster wheel which will provide a uniform biasing force regardless of the wheel vertical position. With such types of casters, uniformity and control of biasing forces is usually sacrificed if vertical adjustment is desired.